package DataStructure.Map;

public class BSTMap<K extends Comparable<K>, V> implements Map<K, V> {
    private Node root;
    private int size;

    public BSTMap() {
        root = null;
        size = 0;
    }

    @Override
    public void add(K key, V value) {
        root = add(root, key, value);
    }

    private Node add(Node node, K key, V value) {
        if (node == null) {
            size++;
            return new Node(key, value);
        }

        if (key.compareTo(node.key) < 0) {
            node.left = add(node.left, key, value);
        } else if (key.compareTo(node.key) > 0) {
            node.right = add(node.right, key, value);
        } else {
            node.value = value;
        }

        return node;
    }

    @Override
    public V get(K key) {
        Node node = get(root, key);
        return node == null ? null : node.value;
    }

    private Node get(Node node, K key) {
        if (node == null) {
            return null;
        }

        if (key.compareTo(node.key) < 0) {
            return get(node.left, key);
        } else if (key.compareTo(node.key) > 0) {
            return get(node.right, key);
        } else {
            return node;
        }
    }

    @Override
    public boolean contain(K key) {
        return get(root, key) != null;
    }

    @Override
    public V remove(K key) {
        Node node = get(root,key);
        if(node == null) {
            throw new IllegalArgumentException("map中不含该key : " + key);
        }
        root = remove(root,key);
        return node.value;
    }

    private Node remove(Node node,K key) {
        if(node == null) {
           return null;
        }
        if(key.compareTo(node.key) < 0) {
            node.left = remove(node.left,key);
            return node;
        } else if(key.compareTo(node.key) > 0) {
            node.right = remove(node.right,key);
            return node;
        } else {
            if(node.left == null) {
                Node rightNode = node.right;
                node.right = null;
                size--;
                return rightNode;
            }

            if(node.right == null) {
                Node leftNode = node.left;
                node.left = null;
                size--;
                return leftNode;
            }

            Node successor = minimum(node.right);
            successor.right =  removeMin(node.right); //important
            successor.left = node.left;


            return successor;
        }
    }

    private Node minimum(Node node) {
        if (node.left == null) {
            return node;
        }

        return minimum(node.left);
    }

    private Node removeMin(Node node) {
        if (node.left == null) {
            Node rightNode = node.right;
            node.right = null;
            size--;
           return rightNode;
        }

        node.left = removeMin(node.left);
        return node;
    }

    @Override
    public void set(K key, V newValue) {
        Node node = get(root, key);
        if (node != null) {
            node.value = newValue;
        }
    }

    @Override
    public int getSize() {
        return size;
    }

    @Override
    public boolean isEmpty() {
        return size == 0;
    }

    private class Node {
        private K key;
        private V value;
        private Node left;
        private Node right;

        public Node(K key, V value) {
            this.key = key;
            this.value = value;
            left = null;
            right = null;
        }

        @Override
        public String toString() {
            String string = "[" + this.key + " : " + this.value + "]";
            return string;
        }
    }

   public void inOrder() {
        inOrder(root);
   }



    private void inOrder(Node node) {
        if(node == null) {
            return;
        }
        inOrder(node.left);
        System.out.println("[" + node.key + " : "  +node.value + "]");
        inOrder(node.right);
        return;
    }
}
